Connecting a tool to a tool holder by the heat shrink method is a well-known process. An example of the general process is described in U.S. Pat. No. 5,311,654 issued to Harold D. Cook on May 17, 1994. The heat shrink process is typically used with a tool holder having a bore for receipt of a tool having a shank. The tool holder is heated to expand the tool holder bore. The shank of the tool is then inserted into the bore. As the tool holder cools, the bore shrinks around the shank holding the shank within the tool holder.
The heat shrink method is an effective method for connecting a tool to a tool holder. However, in most applications, the tool must be precisely mounted within the tool holder or the tool holder cannot be used. It should be appreciated that these tools are typically used in operations that require very precise alignment and positioning. Slight variations in the alignment between tool and tool holder results in the production of defective parts. One of the major disadvantages of known methods for connecting a tool to a tool holder using the heat shrink method is the need to measure each tool and tool holder and the inaccuracy that can result from these repetitive measuring operations. Human error is a significant factor. A worker must measure the tool length and the tool holder length and then adjust the position of the tool to get the appropriate overall length. To reduce human error somewhat, another method employs a pre-qualified measuring rod to determine the appropriate depth of the tool within the tool holder. When this rod wears, the positioning is wrong and resultant tools and tool holders cannot be used. Furthermore, the heat shrink process must be done quickly to avoid down time when changing tools. If the heat shrink method is slow, tool changes will be slow resulting in the overall slowing of the entire operation in which the tool and tool holder are being used.
Accordingly, it would be advantageous to provide a tool assembly unit for rapidly and precisely connecting a tool to a tool holder.